Gainwell is the first freshman in program history to top 200 yards rushing and needed only 14 carries -- a 14.9 average -- to do it.
Memphis (5-0) built a 29-10 lead in the second quarter before Louisiana Monroe got back in it. The Warhawks reduced their deficit to 39-33 with when Caleb Evans threw a 36-yard TD pass to Josh Pederson with 6:31 remaining.
But on the first play after the ensuing kickoff, Gainwell ran for a 68-yard touchdown to extend the lead to 12 points. Following the kickoff, on the Warhawks' first play, La'Andre Thomas intercepted Evans and ran it back 33 yards and a 52-33 lead.
Evans threw for 286 yards and two touchdowns and ran for 112 yards on 18 carries and two scores. Josh Johnson ran for 119 yards on 19 carries for Louisiana Monroe (2-3).
The Warhawks outgained Memphis 575-535 in total yardage but suffered 11 penalties for 114 yards.
Notre Dame athletic director: 'Less likely' that football season starts on time
Notre Dame AD Jack Swarbrick said his belief that the college football season will start on time has "grown more pessimistic" and that it is "less likely" with the ongoing coronavirus pandemic.
Florida, NC State schedule home-and-home football series for 2026, '32
Florida and North Carolina State haven't played in football since the 1992 Gator Bowl, but the schools have set up two future matchups, with the Wolfpack hosting in 2026 and the Gators hosting in 2032.
ACC delaying start of all fall sports until at least Sept. 1
The Atlantic Coast Conference has decided to delay the start of competition in all fall sports until at least Sept. 1, the conference announced Thursday.
Which college football recruiting class had the best group of five-star prospects?
The Class of 2015 had 20 five-star prospects, including Kyler Murray and Derwin James, but it comes down to quality over quantity.
'A labor of love' keeps NCAA Football video game alive
The last edition of the popular EA Sports game debuted seven years ago, but a group of hard-core fans has kept it from going extinct.
Ohio State pauses voluntary on-campus workouts after positive virus tests
Ohio State has paused all voluntary workouts on campus after its latest round of testing for the coronavirus. The decision impacts seven teams, including the football team and men's and women's basketball teams.